Pain is the most frequent reported symptom and is a common clinical problem confronting the clinician. Opioids have long been recognized as one of the most effective treatments of pain whether for treating or preventing cancer pain, central pain, myocardial infarction pain, pancreatic pain, colic pain, post-operative pain, headache pain, muscle pain, bone pain, and pain associated with intensive care. However, the US societal costs of prescription opioid abuse were estimated at more than $50 billion in 2007 and have only grown since.
Transdermal dosage forms offer a favorable route of administration by providing a method of administering sustained release of a drug for an extended period of time, while increasing patient compliance and decreasing extreme peaks and troughs in blood plasma. However, these dosage forms also contain large amounts of active agent and therefore also have a high potential for abuse.
There are many different approaches proposed to prevent abuse of transdermal patches. In particular, U.S. Pat. No. 5,236,714 discloses a dosage form comprising an abusable substance formulated with an antagonist for the abusable substance. U.S. Pat. No. 5,149,538 discloses a transdermal patch comprising an opioid and an antagonist for the opioid that is releasable upon ingestion or solvent immersion, wherein the two reservoirs are separated by an impermeable barrier. U.S. Pat. Nos. 8,747,889, 8,790,689, 7,182,955 each disclose a transdermal patch system comprising an opioid and an antagonist with different methods for the antagonist to leave the patch.
U.S. Pub. No. 20040126323 discloses a transdermal system with an opioid layer and an antagonist layer comprising antagonist salt and base form, both with or without a barrier separating the opioid and antagonist layer.
Although there seems to have been much research in the area, no one has been successful in bringing an abuse deterrent transdermal patch to the market even while the inadvertent misuse or abuse of transdermal dosage forms remains a significant health problem. Thus, there remains a need in the art for improved transdermal dosage forms that are effective for preventing abuse yet useful for delivering an active agent, such as an opioid or a pharmaceutically acceptable salt thereof.